Standing Outside The Fire by Sara Orwig

It began as an anonymous flirtation. Storm raging, lights flickering, two stranded travellers decided to share uninhibited conversation - but no names - during a stolen encounter. Talking turned into kissing...and the need to know each other's names. In an instant, Boone Devlin and Erin Frye discovered they weren't exactly strangers. And Boone discovered that Erin was a virgin.

Only fate could have seen fit to land bachelorhood lovin' Boone in bed with the marriage-minded manager of the Texas ranch he'd inherited and intended to sell. Suddenly, his best-laid plans promised to be the ultimate betrayal. Because Boone was starting to suspect that he and Erin had created a lot more than sparks.